Known in the art are plasma generators, wherein steam is used as a working medium, which can be supplied to the generator from a special source, or be produced immediately in the generator due to high temperatures. The steam generation process can be combined with heat abstraction from the electrodes.
A widespread solution of the problem aimed carrying out said process is supplying the vaporizable fluid through passages in the electrodes, said fluid vaporizing while flowing along said passages, simultaneously cooling the electrodes (PCT/F I 88/00427; SU, A, 1,620,032).
Control over the operating modes of low-temperature plasma generators, triggering mode inclusive, may be carried out by diverse methods. The most widely used method is adjusting the power of the supply source. Another method resides in control of the rate of working medium flow (FR, A, 2 045,865;DE, A1, 3,810,620).
The present invention makes use of a method for control over the plasma torch operating modes by changing the interelectrode gap. The method is a well-known one and can be carried into effect by a number of solutions. In one of such solutions the cathode is connected to the piston of a controlled hydraulic cylinder (EP, A1, 0289961). According to another known solution (EP, A1, 0249238), the electric motor controls, depending on the voltage applied thereto, the position of an axially-movable cathode with respect to a stationary anode.